If you're seeing red on the leaves that wasn't there before, I'd say keep it up and maybe boost the dose a bit, too. A red flush is an indication of magnesium deficiency - magnesium is needed for a plant to make chlorophyll, the green stuff in the leaves.
Probably the plants are metabolizing more slowly due to lower temperatures, so that may be why the magnesium isn't getting absorbed enough. It was extra cold last week too, right? Just guessing here.
I'm just lazy, and my orchids are on an automatic mist system so I don't have to spray anything daily. Once a week is what they get around here, although the mounted orchids and Vandas get watered by the auto-mist every day.
